\section{Introduction}
\paragraph{}Grading assignments at a college level takes time and resources, 
usually in the form of teaching assistants (TA’s).  Professors and TA’s cannot 
easily spend enough time to effectively grade assignments.  Peer grading, where 
identities are known, can be extremely biased and unreliable: if assignments 
are entirely peer-graded, then grades will quickly inflate as students realize 
it is mutually beneficial to give high grades.  We have developed a web-based 
system called CLAPTRAP (Classrooms Leveraging Anonymous Participation to 
Relieve Agonized Professors) which will facilitate peer grading in an 
anonymous web-based format.  To remove incentive to give incorrect 
grades, “expert” graders (professors and TA’s) will grade papers at 
random.  Also, students will be asked to give their own assignments a 
grade.  When the grades are compared, a reputation mechanism will reward 
or penalize the student by adjusting his reputation score.  Much 
research has been done on reputation mechanisms in the marketplace and 
peer-to-peer systems, but little can be found on anonymous systems in an 
obligatory environment free of standard market forces.  This project 
demonstrates that an anonymous grading system could use a modified 
reputation mechanism to create incentives for truthfulness in grading 
and improve grading and feedback in academic settings.
